1. Zika Virus a new global threat
Dr. Ehsan Mostafavi
Leila Molaeipour
Department of Epidemiology &
Research Center for Emerging and Reemerging Infectious Diseases
Pasteur Institute of Iran

2. outline Definition Zika Virus Vectors Modes of Transmission
Zika Virus Epidemiology
Clinical Manifestation
Treatment
Surveillance
Prevention
Pregnancy

3. Zika Virus Single Stranded RNA Virus
Genus Flavivirus, Family Flaviviridae
Closely related to dengue, chikungunya, Japanese encephalitis, yellow fever and Nile Viruses
Transmitted to Humans Primarily by Aedes Species Mosquitoes

4. Zika Virus Vectors Aedes Mosquitoes Aedes species mosquitoes
Ae aegypti: more efficient vectors for humans
Ae albopictus: found in some parts of world
Also transmit dengue and chikungunya viruses
Lay eggs in domestic water-holding containers
Live in and around households
Aggressive daytime biters

5. Aedes aegypti
Aedes albopictus

6. Map showing the distribution of dengue fever in the world, as of 2006
Map showing the distribution of dengue fever in the world, as of Map produced by the Agricultural Research Service of the US Department of Agriculture

7. Worldwide distribution of Aedes albopictus (Stegomyia albopicta) in 2007 original distribution areas where it has been introduced in the last 30 years

8. Modes of Transmission Mosquito Bite Maternal-fetal Other possibilities
From infected to uninfected humans and primates by bite of a mosquito
Maternal-fetal
Intrauterine
Perinatal
Other possibilities
Sexual
Blood transfusion
Theoretical
Organ or tissue transplantation
Breast milk

9. Zika Virus Epidemiology
The first Zika virus was separated during the monitoring yellow fever in a Monkey Rhesus in Uganda in 1947
Human cases of Zika virus was identified in Uganda and Tanzania since 1952
Cases of disease in tropical countries of Asia, including India, Malaysia, Indonesia, Pakistan, and Africa were also reported in
In 2007, first outbreak reported on Yap Island, Federated States of Micronesia
Second and largest outbreak of Zika fever occurred with 28,000 cases occurred in French Polynesia in 2013 and 2014
Then other outbreaks were reported in 3 other islands of the Pacific islands, including Easter Island (Chile), Cook Islands, and New Caledonia.
The cases are reported from Brazil, El Salvador, Guatemala, Mexico, Paraguay, Suriname, Venezuela, French Guiana, Honduras, Panama, Puerto Rico, Bolivia, British Virgin Islands, Costa Rica, the Maldives, Ecuador, and Jamaica since November 2015 to January 2016

10. Zika Virus: Countries and Territories with Active Zika Virus Transmission

11. Zika Virus Incidence and Attack Rates
Infection rate: 73% (95%CI 68–77)
Symptomatic attack rate among infected: 18%(95%Cl 10-27)
All age groups affected
Adults more likely to present for medical care
No severe disease, hospitalizations, or deaths
Note: Rates based on serosurvey on Yap Island, 2007 (population 7,391) Duffy M. N Engl J Med 2009

12. Zika Virus Clinical Disease Course and Outcomes
Clinical illness usually mild
Most common symptoms are a maculo or papular rash, fever, arthralgia, conjunctivitis, myalgia, and headache
Symptoms last several days to a week.
Severe disease requiring hospitalization uncommon
Fatalities are rare, typically only with comorbidities
Guillain-Barré syndrome reported in patients following suspected Zika virus infection Relationship to Zika virus infection is not known

13. Differential Diagnosis for Zika Virus Disease in Returning Travelers
Dengue
Group Astreptococcus
Chikungunya
Rubella
Leptospirosis
Measles
Malaria
Adenovirus
Rickettsia
Enterovirus
Parvovirus

14. Initial Assessment and Treatment
No specific antiviral therapy
Treatment is supportive(i.e., rest, fluids, analgesics , antipyretics)
Suspected Zika virus infections should be evaluated and managed for possible dengue or chikungunya virus infections
Aspirin and other NSAIDs should be avoided until dengue can be ruled out to reduce the risk of hemorrhage

15. Zika Virus Disease Surveillance
Consider in travelers with acute onset of fever, maculopapular rash,
Arthralgia or conjunctivitis with in 2 weeks after return
Inform and evaluate women who traveled to areas with Zika virus
Transmission while they were pregnant
Evaluate fetuses/infants of women infected during pregnancy for possible congenital infection and microcephaly
Be aware of possible local transmission in areas where Aedes species mosquitoes are active.

16. Zika Virus Preventive Measures
No vaccine or medication to prevent infection or disease
Primary prevention measure is to reduce mosquito exposure
Pregnant women should consider postponing travel to areas with ongoing Zika virus outbreaks
Because bites to them may infect mosquitoes, infected people need to be protected from mosquito exposure during first week of illness to prevent further transmission

17. Zika Virus and Pregnancy
Limited information is available
Existing data show:
No evidence of increased susceptibility
Infection can occur in any trimester
Incidence of Zika virus in this population is not known
No evidence of more severe disease
Centers for Disease Control and Prevention, CDC Health Advisory: recognizing Managing and reporting Zika Virus Infections in Travelers Returning from Central America, South America, the aribbean and Mexico,2016.
Besnard, M., et al., Evidence of perinatal transmission of Zika virus, French Polynesia, December 2013 and February 2014.EuroSurveill, (14):p. 1-5.
Oliveira Melo, A.,et al., Zika virus in trauterne infection causes fetal brain abnormality and microcephaly: tip of the ice berg? Ultrasound in Obstetrics& Gynecology, (1):p. 6-7.

18. Maternal-Fetal Transmission of Zika Virus
Evidence of maternal-fetal transmission
Zika virus infection confirmed in infants with microcephaly in Brazil and in infants whose mothers have traveled to Brazil but delivered in the US
Zika virus RNA identified in specimens of fetal losses
Zika virus detected prenatally in amniotic fluid
Two women at ~30 weeks gestation with a history of symptoms consistent
With Zika infection
Fetal microcephaly and intracranial calcifications detected on ultrasound
Amniotic fluid testing positive for Zika virus RNA by RT-PCR

19. Zika Virus and Microcephaly in Brazil
Over 4,000 babies born with microcephaly since outbreak started in in Brazil, an over 20-fold increase
Zika virus infection identified in several infants born with Microcephaly (including deaths) and in early fetal losses
Some of the infants with microcephaly have tested negative for Zika virus
Incidence of microcephaly among fetuses with congenital Zika infection is unknown
Microcephaly can have many causes, not just Zika virus

20. Summary
Zika virus continues to circulate and cause locally-transmitted disease in the world
Consider the possibility of Zika virus infection in travelers with acute fever, rash, arthralgia , or conjunctivitis with in 2 weeks after return
Pregnant women in any trimester should consider postponing travel to areas of Zika virus transmission